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Pulsebeat of early Holocene glaciation in Baffin Bay from high-resolution beryllium-10 moraine chronologies
Quaternary Science Reviews ( IF 3.2 ) Pub Date : 2021-09-21 , DOI: 10.1016/j.quascirev.2021.107179
Nicolás E. Young 1 , Jason P. Briner 2 , Gifford H. Miller 3 , Alia J. Lesnek 4 , Sarah E. Crump 3 , Simon L. Pendleton 5 , Roseanne Schwartz 1 , Joerg M. Schaefer 1
Affiliation  

Beryllium-10 has become the premiere cosmogenic nuclide for quantifying Earth-surface process. Routine measurement of 10Be at the ≤ 2–3% precision level, coupled with precise 10Be production-rate calibrations, now allow for 10Be-based records of glacier and ice-sheet change to be reliably compared to independent records of climate variability. Here, we review efforts over the last 10+ years to characterize the Holocene behavior of ice sheets and glaciers fringing Baffin Bay using in situ 10Be. Hundreds of 10Be measurements present a detailed picture of ice-margin migration through the early Holocene. Widespread net deglaciation was interrupted by ice-margin readvances or stillstands, marked by modes of moraine deposition, near the end of the Younger Dryas (12.9–11.7 ka BP), 10.4–10.2 ka BP, 9.3 ka BP, and 8.2 ka BP, with perhaps additional widespread moraine deposition occurring ca. 9.7 ka BP and 7.3 ka BP. Modes of moraine deposition encompass independent and glaciologically distinct ice masses – the Greenland and Laurentide ice sheets and local alpine glaciers situated on Baffin Island and western Greenland – providing a robust, albeit discontinuous, record of widespread climatic changes in the Baffin Bay region in the early Holocene. Periods of glacier advance coincide with abrupt cooling events documented in Summit Greenland ice cores indicating that i) Baffin Bay ice masses largely followed the pattern of temperature change displayed in Greenland ice cores, ii) abrupt cooling events were of sufficient magnitude and duration to briefly synchronize the behavior of independent and glaciologically distinct ice masses across Baffin Bay despite varying degrees of dynamical influence, and iii) centennial-scale synchronization of ice masses requires that abrupt temperature changes recorded at Summit Greenland also occurred during the summertime within glacier ablation zones. Advancements in 10Be methodology combined with an environment conducive towards developing 10Be-based records of ice-margin change has resulted in ice-margin reconstructions that identify a potentially fundamental negative feedback mechanism inherent to melting ice sheets in the Baffin Bay region – elevated and episodic meltwater delivery into the Labrador Sea results in a decrease in the Atlantic meridional overturning circulation and regional cooling, which, in turn, drives a brief reversal of deglaciation. Under the right conditions 10Be can be used to develop centennial-scale, climatically relevant records of glacier and ice-sheet change.



中文翻译:

从高分辨率铍 10 冰碛年代学看巴芬湾早期全新世冰川的脉搏

铍 10 已成为量化地球表面过程的首要宇宙核素。在 ≤ 2–3% 的精度水平下对10 Be 进行常规测量,再加上精确的10 Be 生产率校准,现在可以将基于10 Be 的冰川和冰盖变化记录可靠地与独立的气候变化记录进行比较. 在这里,我们回顾了过去 10 多年的努力,以使用原位 10 Be来表征巴芬湾边缘的冰盖和冰川的全新世行为。数百个10Be 测量值提供了全新世早期冰缘迁移的详细图像。大范围的净冰消被冰缘再前进或静止物中断,以冰碛沉积模式为标志,在新仙女木末期(12.9-11.7 ka BP)、10.4-10.2 ka BP、9.3 ka BP和8.2 ka BP,大约发生了额外的广泛的冰碛沉积。9.7 ka BP 和 7.3 ka BP。冰碛沉积模式包括独立的和冰川学上不同的冰块——位于巴芬岛和格陵兰西部的格陵兰岛和劳伦泰德冰盖以及当地高山冰川——提供了早期巴芬湾地区广泛气候变化的稳健但不连续的记录全新世。i)巴芬湾冰块在很大程度上遵循格陵兰冰芯中显示的温度变化模式,ii)突然冷却事件的幅度和持续时间足以使整个巴芬湾独立和冰川上不同的冰块的行为短暂同步,尽管不同程度的动力学影响,并且ⅲ)冰群众的百年尺度同步要求急剧的温度变化在记录峰会格陵兰冰川消融区内的在夏季也有发生。10 Be 方法论的进步与有利于发展的环境相结合10以 Be 为基础的冰缘变化记录导致了冰缘重建,确定了巴芬湾地区冰盖融化所固有的潜在基本负反馈机制——向拉布拉多海输送的升高和间歇性融水导致大西洋经向翻转环流和区域变冷,反过来又推动冰川消退的短暂逆转。在适当的条件下,10 Be 可用于开发百年规模的、与气候相关的冰川和冰盖变化记录。

更新日期:2021-09-21
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